有一些正则表达式头痛与各种链接和href分隔符（“和'）

Question

So, I want to match the following link structures with a preg_match_all in php..

<a garbage href="http://this.is.a.link.com/?query=this has invalid spaces" possible garbage>
<a garbage href='http://this.is.a.link.com/?query=this also has has invalid spaces' possible garbage>
<a garbage href=http://this.is.a.link.com/?query=no_spaces_but_no_delimiters possible garbage>
<a garbage href=http://this.is.a.link.com/?query=no_spaces_but_no_delimiters>

I can get " and ' deilmited urls one by doing

'#<a[^>]*?href=("|\')(.*?)("|\')#is'

or I can get all 3, but not if there are spaces in the first two with:

'#<a[^>]*?href=("|\')?(.*?)[\s\"\'>]#is'

How can I formulate this so that it will pick up " and ' delimited with potential spaces, but also properly encoded URLs without delimiters.

Answer 1

OK, this seems to work:

'#<a[^>]*?href=((["\'][^\'"]+["\'])|([^"\'\s>]+))#is'

($matches[1] contains the urls)

Only annoyance is that quoted urls have the quotes still on, so you'll have to strip them off:

$first = substr($match, 0, 1);
if($first == '"' || $first == "'")
    $match = substr($match, 1, -1);